drm/xe: Simplify xe_res_get_buddy()

We can remove the unnecessary indirection thru xe->tiles[] to get
the TTM VRAM manager.  This code can be common for VRAM and STOLEN.
Signed-off-by: Brian Welty <brian.welty@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_res_cursor.h

@@ -50,14 +50,9 @@ struct xe_res_cursor {
 
 static struct drm_buddy *xe_res_get_buddy(struct ttm_resource *res)
 {
-	struct xe_device *xe = ttm_to_xe_device(res->bo->bdev);
 	struct ttm_resource_manager *mgr;
 
-	if (res->mem_type != XE_PL_STOLEN)
-		return &xe->tiles[res->mem_type - XE_PL_VRAM0].mem.vram_mgr->mm;
-
-	mgr = ttm_manager_type(&xe->ttm, XE_PL_STOLEN);
-
+	mgr = ttm_manager_type(res->bo->bdev, res->mem_type);
 	return &to_xe_ttm_vram_mgr(mgr)->mm;
 }